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So it finally turned out to be an artefact, sorry. The probe was protected by a small metallic tube. Somehow water condensed inside. Since this water is isolated from the main liquid, it performed its own phase-transition releasing its latent heat right next to the sensor. The effect was not appreciated when freezing the probe alone. I don't know why, maybe ...


2

You do not explain the context of your analytical problem. One cannot go to an analytical chemist/analysis service and state that tell me all the compounds which are present in this foam. This can take a year. So you have to simplify the problem. (i) If you are solely interested in atomic compositions, all you have to do is to request elemental combustion ...


2

The best way to dissolve a black deposit on glass is to use a concentrated solution of $\ce{NaOH}$, about half water - half $\ce{NaOH}$. But take care ! This dissolution is highly exothermic. Try to prepare not more than a couple of milliliters of it in a test glass tube. The test tube will get hot during the mixing and dissolution operation. And take care ! ...


1

You should not have a single sample preparation for all the elements. The sample preparation will depend on element by element. Your calculations have subtle misconceptions. Don't convert to concentrations but work with masses for such problems. So, you have 15 $\mu$g Mn in 15 g sample. This means you have 1 $\mu$g Mn in 1 g sample (see, I am avoiding ...


1

Yes. There's a knack to it but I have gotten matches to light off of bricks, floor tiles, rocks, painted poles. Strike with force long and hard not gently like with the matchbook


1

A nicely done experiment! Consider hand-warmers containing sodium acetate trihydrate, $\ce{NaCH3COO.3H2O}$. When heated above the melting point and then cooled, the compound does not quickly solidify, but can be greatly supercooled. Given an impetus to begin crystallization, such as the shock-wave produced by a "clicker" (or nucleation by a speck ...


1

Mole merely is a counting (like pair, dozen, hundred) of objects, although a rather large one: $\approx 6.022 \times 10^{23}$. It is used to count electrons (think electrochemistry), atoms, molecules. Gram atom is an outdated unit, superseded by molar mass $M$ which is the mass of of $\pu{1 mol}$ e.g., of atoms (or, more frequently, molecules). Because it ...


1

All i want is a 'yes' if this question is solvable or a no, and maybe a hint as to how i'm supposed to find it? No. The points in the comments are excellent. You need to know something about the amount of water (assuming it is an aqueous solution) or the amount of the finished solution. If you want to use a density table, you need the temperature. Oddly, ...


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